Seawater tolerance and gene expression in two strains of Atlantic salmon smolts

2002 ◽  
Vol 59 (1) ◽  
pp. 125-135 ◽  
Author(s):  
Thomas D Singer ◽  
Koreen M Clements ◽  
Jeffrey W Semple ◽  
Patricia M Schulte ◽  
Jason S Bystriansky ◽  
...  
Keyword(s):  
Gene Expression ◽  
Atlantic Salmon ◽  
Atpase Activity ◽  
Mrna Levels ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Α Subunit ◽  
Seawater Tolerance ◽  
Mrna And Protein Expression ◽  
Or Gene

The seawater tolerance of Atlantic salmon (Salmo salar) smolts reared under identical hatchery conditions was assessed in two Norwegian strains: AquaGen and Imsa. Plasma ion levels were disrupted in both strains following seawater exposure, but these disruptions were more profound in the AquaGen fish. To investigate the mechanisms underlying these differences, we measured gill Na+,K+-adenosine triphosphatase (ATPase) activity and mRNA levels of Na+,K+-ATPase α-subunit and two isoforms of the cystic fibrosis transmembrane conductance regulator (CFTR). Gill Na+,K+-ATPase activity rose significantly in both strains following seawater exposure. Both Na+,K+-ATPase α-subunit and CFTR I mRNA levels were significantly elevated for the entire 2-week period following seawater exposure, whereas CFTR II levels were transiently elevated during the first 24 h only. There were no differences in enzyme activity or gene expression between strains, with the exception of CFTR II, which was significantly lower in the Imsa strain 2 weeks following seawater exposure. This suggests that although changes in mRNA and protein expression for these genes are associated with seawater transfer, they are not the basis of observed physiological differences between strains.

scholarly journals Differential regulation of cystic fibrosis transmembrane conductance regulator and Na+,K+-ATPase in gills of striped bass, Morone saxatilis: effect of salinity and hormones

2007 ◽  
Vol 192 (1) ◽  
pp. 249-260 ◽  
Author(s):  
Steffen Søndergaard Madsen ◽  
Lars Nørholm Jensen ◽  
Christian Kølbæk Tipsmark ◽  
Pia Kiilerich ◽  
Russell John Borski
Keyword(s):  
Cystic Fibrosis ◽  
Atpase Activity ◽  
Striped Bass ◽  
Mrna Level ◽  
Mrna Levels ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Α Subunit ◽  
Igf I ◽  
Cystic Fibrosis Transmembrane

Effects of salinity and hormones on cystic fibrosis transmembrane conductance regulator (CFTR) and α-subunit Na+,K+-ATPase (α-NKA) mRNA (analysed by semi-quantitative PCR) and protein expression (analysed by western blotting and immunocytochemistry) were investigated in gills of striped bass. Freshwater (FW) to seawater (SW) transfer induced a disturbance in serum [Na+]. Gill CFTR protein, mRNA level and Na+,K+-ATPase activity were unaffected by SW transfer, whereas α-NKA mRNA increased after transfer. CFTR immunoreactivity was observed in large cells in FW and SW gill filaments at equal intensity. Cortisol decreased serum [Na+] in FW fish, but had no effect on gill Na+,K+-ATPase activity, α-NKA and CFTR mRNA levels. Incubation of gill tissue with cortisol (24 h, >0.01 μg/ml) and epidermal growth factor (EGF 10 μg/ml) decreased CFTR mRNA levels relative to pre-incubation and control levels. CFTR expression was unaffected by IGF-I (10 μg/ml). α-NKA mRNA levels decreased by 50% after 24 h control incubation; it was slightly stimulated by cortisol and unaffected by IGF-I and EGF. In isolated gill cells, phosphorylation of extracellular-regulated kinase (ERK) 1/2 was stimulated by EGF but not affected by IGF-I. This study is the first to report a branchial EGF response and to demonstrate a functional ERK 1/2 pathway in the teleost gill. In conclusion, CFTR and Na+,K+-ATPase are differentially regulated by salinity and hormones in gills of striped bass, despite the putative involvement of both in salt excretion.

Liver X Receptor β regulates bile volume and the expression of Aquaporins and Cystic Fibrosis Transmembrane Conductance Regulator in the gallbladder

2021 ◽  
Author(s):  
Nathan Sweed ◽  
Hyun-jin Kim ◽  
Kjell Hultenby ◽  
Rodrigo Barros ◽  
Paolo Parini ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Transcription Factor ◽  
Liver X Receptor ◽  
Gallbladder Bile ◽  
Mrna Levels ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Duodenal Ph ◽  
Mrna And Protein Expression ◽  
Cystic Fibrosis Transmembrane

The gallbladder is considered an important organ in maintaining digestive and metabolic homeostasis. Given that therapeutic options for gallbladder diseases are often limited to cholecystectomy, understanding gallbladder pathophysiology is essential in developing novel therapeutic strategies.Since Liver X Receptor β (LXRβ), an oxysterol-activated transcription factor, is strongly expressed in gallbladder cholangiocytes, the aim was to investigate LXRβ physiological function in the gallbladder. Thus, we studied the gallbladders of WT and LXRβ-/- male mice using immunohistochemistry, electron-microscopy, qRT-PCR, bile duct cannulation, bile and blood biochemistry and duodenal pH measurements.LXRβ-/- mice presented a large gallbladder bile volume with high duodenal mRNA levels of the Vasoactive Intestinal Polypeptide (Vip), a strong mediator of gallbladder relaxation. LXRβ-/- gallbladders, showed lower mRNA and protein expression of Aquaporin-1, Aquaporin-8 and Cystic Fibrosis Transmembrane Conductance Regulator (CFTR). A cystic fibrosis-resembling phenotype was evident in the liver showing higher serum cholestatic markers and the presence of reactive cholangiocytes. For LXRβ being a transcription factor, we identified 8 putative binding sites of LXR on the promoter and enhancer of the Cftr gene, suggesting Cftr as a novel LXRβ regulated gene. In conclusion LXRβ was recognized as a regulator of gallbladder bile volume through multiple mechanisms involving CFTR and Aquaporins.

Synthesis of gill Na+-K+-ATPase in Atlantic salmon smolts: differences in α-mRNA and α-protein levels

2000 ◽  
Vol 278 (1) ◽  
pp. R101-R110 ◽  
Author(s):  
Helena D'Cotta ◽  
Claudiane Valotaire ◽  
Florence le Gac ◽  
Patrick Prunet
Keyword(s):  
Atlantic Salmon ◽  
Atpase Activity ◽  
Early Stage ◽  
Polyclonal Antibodies ◽  
Mrna Abundance ◽  
Activity Measurement ◽  
Mrna Levels ◽  
Western Blots ◽  
Α Subunit ◽  
Protein Levels

Several parameters were analyzed to determine the mechanisms responsible for the enhancement of the gill Na+-K+-ATPase activity of Atlantic salmon smolts. A major α-subunit transcript of 3.7 kb was revealed by Northern blot in both parr and smolt gills when hybridized with two distinct cDNA probes. The α-mRNA abundance demonstrated an increase to maximal levels in smolts at an early stage of the parr-smolt transformation. This was followed by a gradual rise in α-protein levels, revealed by Western blots with specific antibodies and by an increase in gill Na+-K+-ATPase hydrolytic activity, both only reaching maximum levels a month later, at the peak of the transformation process. Parr fish experienced a decrease in α-mRNA abundance and had basal levels of α-protein and enzyme activity. Measurement of the binding of [3H]ouabain to Na+-K+-ATPase was characterized in smolts and parr gill membranes showing more than a twofold elevation in smolts and was of high affinity in both groups (dissociation constant = 20–23 nM). Modulation of the enzyme due to increased salinity was also observed in seawater-transferred smolts, as demonstrated by an increase in α-mRNA levels after 24 h with a rise in Na+-K+-ATPase activity occurring only after 11 days. No qualitative change in α-expression was revealed at either the mRNA or protein level. Immunological identification of the α-protein was performed with polyclonal antibodies directed against the rat α-specific isoforms, revealing that parr, freshwater, and seawater smolts have an α3-like isoform. This study shows that the increase in Na+-K+-ATPase activity in smolt gills depends first on an increase in the α-mRNA expression and is followed by a slower rise in α-protein abundance that eventually leads to a higher synthesis of Na+-K+pumps.

Murine colonic mucosa hyperproliferation. II. PKC-β activation and cPKC-mediated cellular CFTR overexpression

2000 ◽  
Vol 278 (5) ◽  
pp. G765-G774 ◽  
Author(s):  
Shahid Umar ◽  
Joseph H. Sellin ◽  
Andrew P. Morris
Keyword(s):  
Cellular Proliferation ◽  
Mrna Levels ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Subcellular Membrane ◽  
Physiol Gastrointest Liver ◽  
Mrna And Protein Expression ◽  
Membrane Bound ◽  
Cystic Fibrosis Transmembrane ◽  
New Hypothesis

In the companion article (Umar S, Scott J, Sellin JH, Dubinsky WP, and Morris AP, Am J Physiol Gastrointest Liver Physiol 278: 753–764, 2000), we have shown that transmissible murine colonic hyperplasia (TMCH) increased cellular cystic fibrosis transmembrane conductance regulator (CFTR) mRNA and protein expression, relocalized CFTR within colonocytes, and enhanced mucosal cAMP-dependent Cl−secretion. We show here that these changes were dependent on elevated cellular levels of membrane-bound Ca2+- and diacylglycerol-sensitive protein kinase C (PKC) activity (12-fold), induced by selective (3- to 4-fold) rises in conventional PKC (cPKC) isoform expression and membrane translocation. Three cPKC isoforms were detected in isolated crypts: α, β1, and β2. cPKC-β1 rises preceded and those of cPKC-α and cPKC-β2 paralleled cellular hyperproliferation and its effects on CFTR expression and cAMP-dependent Cl−current secretion. Only cPKC-β1 and cPKC-β2 were membrane translocated during TMCH. Furthermore, only cPKC-β1 trafficked to the nucleus, whereas cPKC-β2 remained partitioned among cytosolic, membrane, and cytoskeletal subcellular fractions. Modest increases in novel PKC-ε (nPKC-ε) expression and subcellular membrane partitioning were recorded during TMCH, but no changes were seen for PKC-δ or -η. No nPKC isoform nuclear partitioning was detected. The orally bioactive cPKC inhibitor Ro-32–0432 reversed both TMCH and elevated cellular CFTR mRNA levels, whereas a pharmacologically inert analog (Ro-31–6045) failed to inhibit either response. On the basis of these facts, we present a new hypothesis whereby PKC-dependent cellular proliferation promotes endogenous cellular CFTR levels. PKC-β1 was identified as a candidate regulatory PKC isoform.

A Monomer Is the Minimum Functional Unit Required for Channel and ATPase Activity of the Cystic Fibrosis Transmembrane Conductance Regulator†

Biochemistry ◽  
2001 ◽  
Vol 40 (35) ◽  
pp. 10700-10706 ◽  
Author(s):  
Mohabir Ramjeesingh ◽  
Canhui Li ◽  
Ilana Kogan ◽  
Yanchun Wang ◽  
Ling-Jun Huan ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Atpase Activity ◽  
Functional Unit ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Cystic Fibrosis Transmembrane

Gene expression after resumption of development of Artemia franciscana cryptobiotic embryos

1994 ◽  
Vol 72 (3-4) ◽  
pp. 78-83 ◽  
Author(s):  
Ricardo Escalante ◽  
Alberto García-Sáez ◽  
Maria-Asunción Ortega ◽  
Leandro Sastre
Keyword(s):  
Gene Expression ◽  
Time Course ◽  
Developmental Stages ◽  
Artemia Franciscana ◽  
Mrna Levels ◽  
Muscle Actin ◽  
Mrna Accumulation ◽  
Α Subunit ◽  
Steady State Levels ◽  
Cyst Development

The steady-state levels of six different mRNAs have been studied during Artemia franciscana development. Some of these mRNAs are present in the cryptobiotic cyst, like those coding for cytoplasmic actins, sarcoplasmic/endoplasmic reticulum Ca2+-ATPase, and the Na+,K+-ATPase α-subunit isoform coded by the clone pArATNa136. The expression of these mRNAs is markedly induced during cyst development. A small increase in mRNA levels can be observed for some genes at very early stages of development (2 h). The main increase is observed between 4 and 16 h of development for all these genes, although the time course of mRNA accumulation is different for each one of the genes studied. Some other genes, like those coding for muscle actin (actin 3) or the Na+,K+-ATPase α-subunit isoform coded by the cDNA clone α2850, are not expressed in the cyst before resumption of development and their expression is induced after 10 or 6 h of development, respectively. These data on the kinetic of mRNA accumulation provide the information required to determine transcriptionally active developmental stages, necessary to study in more detail the mechanisms of transcriptional regulation during activation of cryptobiotic cysts and resumption of embryonic development.Key words: Artemia, gene expression, actin, Na,K-ATPase, Ca2+-ATPase.

Serum transcriptionally regulates Na(+)-K(+)-ATPase gene expression in vascular smooth muscle cells

1997 ◽  
Vol 273 (3) ◽  
pp. C1088-C1099 ◽  
Author(s):  
J. Nemoto ◽  
S. Muto ◽  
A. Ohtaka ◽  
K. Kawakami ◽  
Y. Asano
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Atpase Activity ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Fold Increase ◽  
Mrna Levels ◽  
Subunit Protein ◽  
Mrna Induction

The present study was designed to examine the effects of serum on Na(+)-K(+)-ATPase alpha 1- and beta 1-subunit gene expression in cultured vascular smooth muscle cells (VSMC) from rat thoracic aortas. Addition of 10% serum to VSMC for 24 h increased Na(+)-K(+)-ATPase activity 1.5-fold and alpha 1- and beta 1-subunit protein levels 1.9-fold. Serum (10%) caused a 3.5-fold increase in alpha 1-mRNA levels and a 6.7-fold increase in beta 1-mRNA levels, with peak elevations at 12 h. The protein synthesis inhibitor cycloheximide abolished serum-mediated beta 1-mRNA induction but did not affect serum-mediated alpha 1-mRNA induction. Protein kinase C (PKC) inhibitors (staurosporine A or calphostin C) or tyrosine kinase (TK) inhibitors (genistein or herbimycin A) significantly reduced serum-mediated beta 1-mRNA induction but had no effect on serum-mediated alpha 1-mRNA induction. Transfection experiments with the 5'-flanking sequences of the alpha 1- or beta 1-subunit genes linked to the luciferase reporter gene revealed that 10% serum caused 2.8- and 6.5-fold increases in luciferase activity, respectively. Among growth factors, only basic fibroblast growth factor (FGF) enhanced luciferase activities for the alpha 1- and beta 1-subunit genes. We conclude that 1) serum stimulates alpha 1- and beta 1-mRNA expression, alpha 1- and beta 1-subunit protein accumulation, and Na(+)-K(+)-ATPase activity; 2) serum-mediated beta 1-mRNA induction partly requires de novo synthesis of intermediate regulatory proteins and activation of PKC and TK, whereas serum-mediated alpha 1-mRNA induction occurs through PKC- and TK-independent mechanisms; 3) the 5'-flanking regions of the alpha 1- and beta 1-subunit genes are serum responsive; and 4) FGF mimics stimulatory effects of serum on promoter activities for the alpha 1- and beta 1-subunit genes.

scholarly journals Regulation of pituitary inhibin/activin subunits and follistatin gene expression by GnRH in female rats

2011 ◽  
Vol 210 (1) ◽  
pp. 71-79 ◽  
Author(s):  
Petra Popovics ◽  
Zoltan Rekasi ◽  
Alan J Stewart ◽  
Magdolna Kovacs
Keyword(s):  
Gene Expression ◽  
Mrna Level ◽  
Inhibin B ◽  
Female Rats ◽  
Pituitary Cells ◽  
Mrna Levels ◽  
Short Term ◽  
Α Subunit ◽  
Long Term Treatment

Pituitary inhibin B, activin B, and follistatin are local regulators of FSH. Activin B is a homodimeric molecule (βB–βB), while inhibin B contains an α and a βB subunit. The regulation of gene expression of α, βB, and follistatin by local and endocrine hormones was examined in pituitaries from female rats and in perifused pituitary cells by RT-PCR. Ovariectomy (OVX) induced an elevation in the mRNA level of α and βB subunits and follistatin. Short-term (4 h) treatment of pituitary cells with GnRH decreased both the inhibin α and the inhibin/activin βB subunit mRNA levels, while long-term treatment (20 h) with 100 nM GnRH stimulated the expression of both subunits. In contrast, the mRNA level of follistatin was elevated after the short-term GnRH treatment. Long-term exposure of pituitary cells to estradiol and inhibin B suppressed the mRNA expression of βB and had no effect on the expression of α subunit and follistatin. Our results demonstrate that the increased expressions of inhibin/activin subunits and follistatin in the post-OVX period can be induced by the lack of gonadal negative feedback, resulting in a high GnRH environment in the pituitary. This study reports for the first time that GnRH administered in high doses and for a long period stimulates the gene expression of inhibin/activin subunits and thereby may contribute to the stimulatory effect of OVX on the expression of these genes.

Effects of Acid Water and Aluminum on Parr–Smolt Transformation and Seawater Tolerance in Atlantic Salmon, Salmo salar

1993 ◽  
Vol 50 (9) ◽  
pp. 1816-1827 ◽  
Author(s):  
Magne Staurnes ◽  
Per Blix ◽  
Ola B. Reite
Keyword(s):  
Carbonic Anhydrase ◽  
Atlantic Salmon ◽  
Atpase Activity ◽  
Salmo Salar ◽  
Carbonic Anhydrase Activity ◽  
Low Ph ◽  
Soft Water ◽  
Control Fish ◽  
Exposed Fish ◽  
Seawater Tolerance

Smolting Atlantic salmon, Salmo salar, were kept from 11 April to 24 May in soft water of pH 5 or in soft water of pH 5 and 50 μg aluminum (Al)∙L−1. Control fish were kept in soft water of pH 6.3–6.5. Water temperature was 8–14 °C. In mid-May, some of the control smolts were transferred to the test conditions for 8 d. Exposure to acid water resulted in osmoregulatory failure and high mortality rate. Al strongly enhanced toxicity. Sensitivity to low pH or low pH/Al exposure greatly increased when fish had developed to seawater tolerant smolts. In control and acid-exposed fish, gill carbonic anhydrase activity remained unchanged throughout the experiment whereas in Al-exposed fish, carbonic anhydrase activity decreased. Gill Na+K+-ATPase activity in control fish peaked in mid-May simulanteously with development of seawater tolerance. Fish from both acid-exposed groups had low seawater tolerance. Na+,K+-ATPase activity declined to 60% of start value in acid-exposed fish and to parr level in Al-exposed fish. Hypoosmoregulatory ability was linearly correlated with gill Na+K+-ATPase activity. Reduction in plasma Na+ concentration in acid-exposed fish was linearly correlated with the reduction in gill Na+,K+-ATPase activity.

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